Affiliation: Department of Biochemistry, Ege University, Faculty of Medicine, Bornova Izmir, Turkey
Dietary antioxidants exhibit their antioxidant properties mainly through the inhibition of low density lipoprotein oxidation and cellular lipid peroxidation and / or preserving the cellular antioxidant pool and / or potentiation of each others beneficial effects. Recent studies also demonstrated an association between increased intake of these dietary components and reduced risk for diseases in which inflammatory processes as well as oxidant stress are accused to have an aethiopathological role. Thus, besides their known antioxidant effects, new evidence attributes an antiinflammatory role for these agents. Alterations in the intake of antioxidant nutrients affect the progress of inflammation mainly by interacting with generation of ROS / RNS by activated phagocytes. Reducing structures found in dietary antioxidants depress activation of NF-kB, and upregulation of COX-2, iNOS and adhesion molecules involved in phagocyte recruitment. Thus nutritional modulation may indeed represent a safe and effective way for the prevention of pathologies in which both oxidation and inflammation play fundamental roles. Given the exciting evidence for a protective effect of dietary antioxidants in inflammatory processes, future research investigating the effects of these nutrients on multiple aspects of the inflammatory response deserves further attention. This review concentrates on the biochemical and metabolic aspects of 4 major groups of dietary antioxidants: vitamin C, vitamin E, carotenoids and plant phenols. Oxidant stress and inflammation mechanisms are reviewed before discussing some key points and unresolved issues related to the antiinflammatory effects of antioxidant nutrients. The last part of the review gives particular emphasis to atherosclerosis and Alzheimers Disease. Finally, some future research and the development of new antiinflammatory agents is proposed based on the antiinflammatory effects of dietary antioxidants.